IS 16052 (Part 4) : 2013 ISO 13765-4 : 2004 Hkkjrh; ekud vfXulg eksVkZlZ Hkkx 4 vkueu'khy cačku lkeF;Z Kkr djuk Indian Standard REFRACTORY MORTARS PART 4 DETERMINATION OF FLEXURAL BONDING STRENGTH ICS 81.080 © BIS 2013 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 February 2013 Price Group 3 Refractories Sectional Committee, MTD 15 NATIONAL FOREWORD This Indian Standard (Part 4) which is identical with ISO 13765-4 : 2004 `Refractory mortars -- Part 4: Determination of flexural bonding strength' issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Refractories Sectional Committee and approval of the Metallurgical Engineering Division Council. This standard is published in various parts. Other parts in this series are: Part 1 Determination of consistency using the penetrating cone method Part 2 Determination of consistency using the reciprocating flow table method Part 3 Determination of joint stability Part 5 Determination of grain size distribution (sieve analysis) Part 6 Determination of moisture content of ready-mixed mortars The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following: a) Wherever the words `International Standard' appear, referring to this standard, they should be read as `Indian Standard'. b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker. c) In clause 7.1.2, number of test pieces have been mentioned. However, number of test pieces can also be taken by mutual agreement between the purchaser and the manufacturer. In clause 7.2, procedure for the drying of the test specimen is specified. Alternatively, the test specimen can be put into the drying oven at 110 ± 5oC and held for 16 h. In this adopted standard, reference appears to certain International Standards for which Indian Standards also exist. The corresponding Indian Standards which are to be substituted in their respective places are listed below along with their degree of equivalence for the editions indicated: International Standard ISO 8656-1 Refractory products -- Sampling of raw materials and unshaped products -- Part 1: Sampling scheme ISO 13765-1 : 2004 Refractory mortars -- Part 1: Determination of consistency using the penetrating cone method ISO 13765-2 : 2004 Refractory mortars -- Part 2: Determination of consistency using the reciprocating flow table method Corresponding Indian Standard Degree of Equivalence IS 1528 (Part 7) : 2011 Methods of Technically Equivalent sampling and physical tests for refractory materials: Part 7 Methods of sampling and criteria for conformity (second revision) Identical IS 16052 (Part 1) : 2013 Refractory mortars: Part 1 Determination of consistency using the penetrating cone method do IS 16052 (Part 2) : 2013 Refractory mortars: Part 2 Determination of consistency using the reciprocating flow table method For the purpose of deciding whether a particular requirement of this standard is complied with the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 `Rules for rounding off numerical values (revised)'. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. IS 16052 (Part 4) : 2013 ISO 13765-4 : 2004 Indian Standard REFRACTORY MORTARS PART 4 DETERMINATION OF FLEXURAL BONDING STRENGTH 1 Scope This part of ISO 13765 describes a method of determination of the flexural bonding strength of the bonded face between refractory bricks laid with refractory mortars (after drying and firing). 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 8656-1, Refractory products -- Sampling of raw materials and unshaped products -- Part 1: Sampling scheme ISO 13765-1, Refractory mortars -- Part 1: Determination of consistency using the penetrating cone method ISO 13765-2, Refractory mortars -- Part 2: Determination of consistency using the reciprocating flow table method 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 flexural bonding strength maximum stress that a specimen can withstand when it is bent on a three-point bending device 4 Principle A prismatic specimen of a given size is made by bonding two test pieces of refractory brick with the refractory mortar to be tested. After drying and firing, a bending stress is applied at a given loading rate on the bonding face of the specimen at room temperature until failure of the bonding face occurs. 5 Apparatus 5.1 Loading device, consisting of two bearing edges and a loading edge which are parallel to each other, as shown in Figure 1. The loading edge shall be located between, and isometric to, the two bearing edges. The values of Ls and R, the tolerances for the parallelism of the cross section sides and the parallelism of the top and bottom faces shall be as specified in Table 1. The loading device shall be able to apply a load at a uniform rate on the middle of the specimen and have the loading rate shown in Table 1. 5.2 Mixer, as specified in ISO 13765-1 or ISO 13765-2. 1 IS 16052 (Part 4) : 2013 ISO 13765-4 : 2004 Dimensions in millimetres Key Ls R distance between the supports radius of curvature of the loading edge and bearing edges Figure 1 -- Loading device Table 1 -- Dimensions, tolerances and loading rates associated with test pieces of various sizes Tolerance Tolerance Test piece size Tolerance for for the for the the breadth, b, and height, h parallelism of parallelism of the top and the crosssection sides bottom faces Distance between the supports Radius of curvature, R, of the loading edge and bearing edges Loading rate Ls l × b × h Dense shape mm 115 × 114 × 76 115 × 114 × 64 100 × 40 × 40 57,5 × 25 × 25 57 × 40 × 40 N/s Insulating shape mm 120 ± 12 86 ± 8,6 12 ± 1,2 4,2 ± 0,42 21 ± 2,1 mm -- -- mm -- -- mm -- -- mm 180 ± 1 180 ± 1 180 ± 1 100 ± 1 100 ± 1 mm 15 ± 0,5 15 ± 0,5 5 ± 0,5 5 ± 0,5 4 ± 0,5 mm 370 ± 37 260 ± 26 36 ± 3,6 13 ± 1,3 64 ± 6,4 ±1 ±1 ±1 ± 0,15 ± 0,1 ± 0,15 ± 0,25 ± 0,2 ± 0,25 5.3 Electrical drying oven, fitted with a temperature controller and capable of operating at 110 C ± 5 C. 5.4 Consistency determining device, as specified in ISO 13765-1 or ISO 13765-2. 5.5 Balance, with a maximum weighing capacity of 2 kg and capable of weighing to the nearest 1 g. 5.6 Callipers, capable of measuring to the nearest 0,1 mm. 5.7 Furnace, capable of meeting the heating requirements specified in 7.3. 5.8 Thermocouple pyrometer. 2 IS 16052 (Part 4) : 2013 ISO 13765-4 : 2004 5.9 Cutting tool. 6 Sampling and preparation of the test pieces 6.1 Sampling For dry mortar, sample the mortar in accordance with ISO 8656-1 or as agreed between parties. Reduce the sample to 5 kg by quartering or with a riffle sampler. Sample ready-mixed mortars by emptying the entire contents of the container in which the mortar is supplied into another container of larger capacity and mixing thoroughly. It is important that any supernatant liquid not be discarded. Ensure that a representative sample of the wet mixture is obtained. 6.2 Preparation of the test pieces The size of the test pieces is shown in Table 1. The actual dimensions used shall be agreed upon between parties prior to testing. Ten test pieces are required. These are used for making five test specimens, each specimen being constituted of two test pieces bonded with mortar. Cut test pieces from the refractory bricks for test following the sizes and the tolerances shown in Table 1. The adjacent edges of the test pieces shall be perpendicular to each other and the corners shall be square. The surfaces of the test pieces shall be smooth and have no cracks and the faces to be bonded shall be clean. Each test piece shall have an uncut face for bonding. The bricks used in the test shall be compatible with the mortar being tested. Before testing, place the test pieces in the drying oven, raise the temperature to 110 C ± 5 C and keep for 8 h or until constant weight is achieved. Then cool to room temperature naturally. 7 Procedure 7.1 Preparation of the test specimens 7.1.1 For dry mortars, take 1,5 kg using the balance and mix with water in accordance with ISO 13765-1 or ISO 13765-2 to attain the desired consistency. Determine the consistency and allow to rest for 30 min or in accordance with the manufacturer's instructions. For wet mortars, mix thoroughly and then take about 1 kg. After determining the consistency, carry out the procedures described in 7.1.2. 7.1.2 Take a pair of dried test pieces and apply a layer of the well-mixed mortar to both of the uncut faces and then remove the mortar. Apply the mortar again to both of the uncut faces and then join the two mortar-covered faces together (see Figure 2). Force out the excess mortar to form a joint of 2 mm, unless otherwise agreed, by pressing the top test piece and at the same time moving it laterally. Remove the excess mortar forced out. The specimen shall not be wrapped and the displacement shall not be greater than 0,5 mm. Repeat the above operation using the 10 test pieces to make five specimens. 3 IS 16052 (Part 4) : 2013 ISO 13765-4 : 2004 Key 1 mortar Figure 2 -- Test specimen 7.2 Drying the test specimens Air dry the test specimens naturally at room temperature for 24 h, with each specimen resting on a face parallel to the bonded face. Carefully place the air-dried specimens on a face parallel to the bonded face in the drying oven. Raise the temperature to 65 C ± 5 C and hold for 4 h. Then raise the temperature to 110 C ± 5 C and hold for 12 h. 7.3 Firing the test specimens Place the dried specimens on the soaking zone of the furnace. The distance between the specimens themselves and that between the specimens and the soaking plates shall not be less than 10 mm. The distance between the specimens and the heating element shall not be less than 20 mm. If the soaking plates are absent, the radiant heat of the heating elements shall not directly reach the bonded faces of the specimens. When heating, maintain an oxidizing atmosphere in the furnace. Use the following heating rates: -- normally 5 C/min; -- silica mortar 3 C/min. When the specified temperature is reached, hold for 3 h (5 h for silica-based mortar), over which the fluctuation of the temperature shall not exceed ± 10 C. After the holding period, cool the specimens in the furnace to room temperature naturally. 7.4 Determination of flexural bonding strength 7.4.1 Measure the width, b, and height, h, of each test specimen at the bonded faces after drying and firing. Take two measurements at different points for each test specimen. Calculate the mean value to the nearest 0,1 mm for each test specimen. 7.4.2 Place a specimen on the bearing edges. Align the loading edge with the joint of the specimen. The deviation shall not exceed 2 mm. Apply load vertically at a rate specified in Table 1 until the failure of the bonded face occurs. Record the maximum load. 4 IS 16052 (Part 4) : 2013 ISO 13765-4 : 2004 7.4.3 Inspect the specimens one by one with care. If the area of voids in the bonded face of a specimen is 20 % or more, or the full bonded face of a specimen is clean and smooth, disregard that result. In this case, if the normal specimens are less than three, conduct the test again from 6.2. 8 Calculation Calculate the flexural bonding strength for each test specimen as the modulus of rupture, F , in megapascals, to the nearest 0,1 MPa, using the equation F = where 3 Fmax Ls 2 bh2 Fmax is the maximum force exerted on the specimen, in newtons; Ls b h is the distance between the supports, in millimetres; is the width of the specimen at the bonded face, in millimetres; is the height of the specimen at the bonded face, in millimetres. Report the result as the mean of the five determinations, excluding any disregarded in accordance with 7.4.3, to the nearest 0,1 MPa. 9 Test report The test report shall include the following information: a) all information necessary for identification of the material tested, including a description of the material, manufacturer, type, brand, batch number, size of test pieces, etc.; b) a reference to this part of ISO 13765 (ISO 13765-4); c) the name of the testing establishment; d) in the case of a dry mortar, the percentage of water (or specified liquid) added; e) the results of the test, i.e. the flexural bonding strength in megapascals, including the results of the individual determinations and their mean, calculated as specified in Clause 8, and noting if the failure did not occur at the bonded face; f) the consistency of the mortar tested and the method used to determine the consistency, i.e. ISO 13765-1 or ISO 13765-2; g) the firing temperature and holding time; h) any deviations from the procedure specified; i) j) any unusual features (anomalies) observed during the test; the date of the test. 5 Bureau of Indian Standards BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote harmonious development of the activities of standardization, marking and quality certification of goods and attending to connected matters in the country. 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